1. FIELD OF THE INVENTION
The present invention relates to a prime-motor-driven room warming/cooling and hot water supplying apparatus in which a compressor for a heat pump is driven by a prime motor and a heat generated from the motor is recovered and utilized as auxiliary heat sources for room warming and hot water supplying.
2. DISCUSSION OF THE BACKGROUND
There have been proposed two types of prime-motor-driven room warming/cooling and hot water supplying apparatus, i.e. one in which cooling water for cooling a prime motor is directly introduced into a heat radiator placed in a room to warm the room and the other in which a refrigerant in a heat pump circuit is heated by cooling water for cooling the prime motor so that the heated refrigerant is utilized for room warming.
FIG. 7 is a diagram showing a refrigerant and hot water circuit used for the latter type of the apparatus.
In FIG. 7, a reference numeral 1 designates a prime motor, a numeral 2 a clutch, a numeral 3 a compressor connected to the prime motor 1 through the clutch 2, a numeral 4 a four-way valve, a numeral 5 a room side heat exchanger, a numeral 6 a room side air blower for the room side heat exchanger 5, a numeral 7 an outdoor side heat exchanger, a numeral 8 an outdoor air blower for the outdoor side heat exchanger 7, a numeral 9 a receiver, and a numeral 10 a throttling device such as an expansion valve. The compressor 3, the room side heat exchanger 5, the outdoor side heat exchanger 7, the receiver 9 and the throttling device 10 are connected by tubes to form a heat pump circuit 30. Check valves 11-14 and electromagnetic valves 15, 16 are also interposed in the heat pump circuit 30. A supplied water circuit 31 is connected to the heat pump circuit 30 through the electromagnetic valve 16, and the water heating circuit 31 is formed by connecting a water tank 19, a water circulating pump 20, a first heat exchanger 17 for exchanging heat between the refrigerant in the heat pump circuit 30 and water to be supplied from the water tank 19 and a second heat exchanger 18 for exchanging heat between water for cooling the prime motor 1 and the water supplied from the water tank 19. The water tank 19 is provided with a water feeding pipe 21 at its bottom and a water feeding valve 22 at its upper part.
A cooling water circulating circuit 32 comprises a cooling system provided in the prime motor 1, a cooling water pump 23, an electromagnetic valve 24 and the second heat exchanger 18. A series connection of on electromagnetic valve 25 and a refrigerant heating heat exchanger 27 is connected in parallel to the cooling water circulating circuit 32 with respect to the prime motor 1.
A refrigerant heating circuit 33 comprises a refrigerant feeding pump 26, the refrigerant heating heat exchanger 27 and a check valve 28, and it extends from a joint portion between the receiver 9 and the throttling device 10 of the heat pump circuit 30 to a joint portion between the four-way valve 4 and the room side heat exchanger 5. The electromagnetic valve 15 is interposed between the four-way valve 4 and the room side heat exchanger 5.
A piping arrangement including the room side heat exchanger 5, the electromagnetic valves 16, and a first heat exchanger 17 for exchanging heat between the refrigerant and water to be supplied from the water tank 19 constitutes a supplied water heating circuit 34. A reference numeral 35 designates a water temperature sensor.
The operation of the conventional room warming/cooling and hot water supplying apparatus having the construction as above-mentioned will be described.
The operation for room cooling or room warming is performed by a known heat pump method by switching the four-way valve 4. Namely, in the room cooling operation, heat is taken from a room air by the room side heat exchanger 5 and the heat is radiated outside by the outdoor side heat exchanger 7. In the room warming operation, heat is taken from the atmosphere by the outdoor side heat exchanger 7 and the heat is radiated in the room by the room side heat exchanger 5. The check valves 11, 12, 13, 14 function to feed the refrigerant from the receiver 9 to the throttling device 10 by switching the four-way valve 4.
In the operation for heating water by utilizing the heat pump, the electromagnetic valve 15 is closed and the electromagnetic valve 16 is opened so that the heat of the refrigerant is radiated at the first heat exchanger (in this case, heat is taken from the outer air by means of the outdoor side heat exchanger 7). On the other hand, water is forcibly supplied from the water tank 19 by the water circulating pump 20 to be introduced in the first exchanger 17 where the water is heated by heat-exchanging with the refrigerant, and then the hot water is returned to the water tank 19.
During room warming, room cooling or hot water supplying operation, the compressor 3 is driven by the prime motor 1. Therefore, it is necessary to cool the prime motor. For this, the cooling water is circulated in the cooling water circulating circuit 32 by the cooling water pump 23. Namely, the cooling water is circulated in the course of the cooling water pump 23, the prime motor 1, the electromagnetic valve 24, the second heat exchanger 18 where the temperature of the cooling water is elevated at a high level by a waste heat from the prime motor 1. The water from the water tank 19 is circulated in the supplied water circuit 31 in the course of the water tank 19, the water circulating pump 20, the first heat exchanger 17, the second heat exchanger 18 to be returned to the tank 19. Since the electromagnetic valve 16 is closed during the room cooling or the room warming operation, the water is heated by only the second heat exchanger 18. However, in the hot water supplying operation by utilizing the heat pump, the water is heated by both the first and second heat exchangers 17, 18 by closing the electromagnetic valve 15 while the electromagnetic valve 16 opened. The cooling water circulating pump 20 is usually operated since the waste heat from the prime motor 1 can be utilized to elevate the temperature of the cooling water.
When a load for room warming is relatively high in the room warming operation and the temperature of water in the water tank 19 becomes higher than that of the cooling water for cooling the prime motor 1, it is impossible to radiate the heat in the cooling water in the second heat exchanger 18. In this case, the electromagnetic valve 24 is closed and at the same time the electromagnetic valve 25 is opened whereby the cooling water is circulated in the refrigerant heating heat exchanger 27. At the same time, the refrigerant pump 26 is driven to perform heat-exchanging, in the refrigerant heating heat exchanger 27, between the cooling water for the prime motor 1 and the liquefied refrigerant in the receiver 9. Then, the temperature of the cooling water is decreased and the liquefied refrigerant from the receiver 9 becomes gas, which is passed through the check valve 28 and is combined with the refrigerant supplied from the compressor 3 through the four-way valve 4. The refrigerant is fed into the room side heat exchanger 5 where heat is radiated in the room. Thus, an additional amount of the refrigerant from the receiver 9 is combined with an amount of the refrigerant from the compressor 3, which is fed at the ordinary rate, and accordingly, the increased amount of the refrigerant is supplied to the room side heat exchanger 5 to thereby enhance the performance of room warming operation of the room side heat exchanger 5. Thus, the heat generated from the prime motor is utilized to prevent reduction in the performance of the room warming in the case that the outer temperature is low while a load of room warming is large.
When the temperature of the water in the water tank 19 increases and it is difficult to heat the water in the water tank 19 by the heat of the cooling water for the prime motor 1, the water temperature sensor 35 detects the temperature of the cooling water so that the electromagnetic valves 24, 25 are operated to circulate the cooling water to the refrigerant heating heat exchanger 27.
Thus, in the conventional room warming/cooling and hot water supplying apparatus constructed as above-mentioned, it is necessary to provide in an outdoor unit with the refrigerant heating heat exchanger 27, the first heat exchanger 17 for transmitting the heat of the refrigerant to the water to be supplied to the oil tank and the second heat exchanger 18 for transmitting the heat of the cooling water to the water to be supplied to the water tank. Further, since the heat exchanging is carried out between the refrigerant flowing in the refrigerant heating circuit 33 and the cooling water in the refrigerant heating heat exchanger 27 by switching the electromagnetic valves 24, 25 during the room warming operation, it is necessary to provide the water temperature sensor 35 for detecting the temperature of the cooling water for cooling the prime motor 1 and the electromagnetic valves 24, 25 for switching the cooling water circulating circuit 32. In addition, it is also necessary to provide a space for locating the refrigerant heating heat exchanger 27 and the second heat exchanger 18. Accordingly, the volume and the weight of the apparatus become large.
Although the prime-motor-driven room warming/cooling and hot water supplying apparatus reduces cost for operations in comparison with the apparatus of an electric-motor-driven type, it requires the prime motor and its accessories, which inevitably increase the weight and the installation space. An attempt of improving the performance of room warming by heating the refrigerant, increases the number of heat exchangers thereby resulting in increase of weight and the manufacturing cost.